When both surfaces of a wafer are polished simultaneously by polishing processing and the like, the wafer is held by a carrier for a double-side polishing apparatus.
FIG. 8 is a schematic explanatory view explaining polishing of the wafer by a general double-side polishing apparatus that has been conventionally used. As shown in FIG. 8, the carrier 101 for a double-side polishing apparatus is formed to have a thickness thinner than that of the wafer W, and has a holding hole 104 for holding the wafer W at a predetermined position between an upper turn table 108 and a lower turn table 109 of the double-side polishing apparatus 120.
The wafer W is inserted into the holding hole 104 to hold it, and upper and lower surfaces of the wafer W are sandwiched by polishing pads 110 attached on surfaces of the upper turn table 108 and the lower turn table 109, facing to the wafer.
The carrier 101 for a double-side polishing apparatus is engaged with a sun gear 111 and an internal gear 112, and is rotated and revolved by driving to rotate the sun gear 111. Both surfaces of the wafer W are polished simultaneously with the polishing pads 110 attached to the upper and lower turn tables by rotating the upper turn table 108 and the lower turn table 109 in an opposite direction to each other, while supplying a polishing agent to the surfaces to be polished.
The above-described carrier 101 for a double-side polishing apparatus used in a double-side polishing process of the wafer W is mostly made of metal. A resin insert 103 is therefore attached along an inner circumference of the holding hole 104 formed in a carrier body 102 in order to protect a peripheral portion of the wafer W from damage caused by the metal carrier 101. With regard to attachment of the resin insert, it has been conventionally known that an outer circumferential portion of the resin insert is formed into a wedge shape, fitted into the carrier body, and further fixed by an adhesive in order to prevent the resin insert from coming off during processing and conveying the wafer (See Patent Literature 1).
When the wafer W is polished with the above-described double-side polishing apparatus 120, however, a sag may be generated at an outer circumference of the wafer W, and nano-topology failure may be generated in some cases.